How do I test a 18650 battery?

apples

Newly Enlightened
Joined
Aug 23, 2009
Messages
42
The old laptop only holds charge for 20mins or so. I carefully tried to pry apart the battery pack, and that was a disaster. All the plastic cracked and fell apart in small bits, could not believe it.

Anyway I have charged up all six individual batteries using my [COLOR=rgba(0, 0, 0, 0.870588)]Nitecore i2 Intellicharge Charger.

All six batteries seemed to charge fine. But this charger will not tell me capacity of the batteries.

I have read that the charging circuits on some laptops have a memory chip that will give a signal of a dud battery pack after x amount of charges regardless of the batteries real condition?

1. How can I check the capacity of my batteries.
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WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
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3,967
Location
Canada
For checking capacity, you need a charger that does discharge tests. I use the Liitokala Li-500 for that kind of stuff. It will charge the batteries to full (4.2v), then discharge them down to 2.8v, measuring the total mAh of capacity over that time. There are many chargers that do discharge testing. Don't bother with chargers that only tell you how many mAh they use during charging; that's usually not very accurate.
 

StorminMatt

Flashlight Enthusiast
Joined
Oct 30, 2012
Messages
2,263
Location
Norcal
There are other tests you can do if you don't have a charger that can measure capacity. One is a runtime test. If there is a cell (or more) that can't run your light as long as the others, you know it is bad. Also, a bad battery may not be able to properly run a light on its highest setting. Or it may rest at an abnormally low voltage after charging.
 
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